Method for forming photoresist layer

ABSTRACT

A method for forming a photoresist layer includes the following steps. A first photoresist layer is formed on a first wafer provided on a platen. The platen includes a plurality of temperature zones being at a first set of process temperatures. A first etching process is performed on the first wafer to form a first patterned metal layer. A profile variation of the first patterned metal layer with respect to a reference profile is determined. The first set of process temperatures is adjusted to a second set of process temperatures according to the profile variation. A second photoresist layer is formed on a second wafer provided on the platen with the temperature zones being at the second set of process temperatures respectively.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of and claims the prioritybenefit of a prior application Ser. No. 15/884,299, filed on Jan. 30,2018. The entirety of each of the above-mentioned patent applications ishereby incorporated by reference herein and made a part of thisspecification.

BACKGROUND

Semiconductor devices are used in a variety of electronic applications,such as personal computers, cell phones, digital cameras, and otherelectronic equipment. Semiconductor devices are typically fabricated bysequentially depositing insulating or dielectric layers, conductivelayers, and semiconductor layers of material over a semiconductorsubstrate, and patterning the various material layers using lithographyto form circuit components and elements thereon. Many integratedcircuits are typically manufactured on a single semiconductor wafer. Thedies of the wafer may be processed and packaged at the wafer level, andvarious technologies have been developed for wafer level packaging.

The numerous processing steps are used to cumulatively apply multipleelectrically conductive and insulating layers on the wafer and patternthe layers to form the circuits. The final yield of functional circuitson the wafer depends on proper application of each layer during theprocess steps. Proper application of those layers depends, in turn, oncoating the material in a uniform spread over the surface of the waferin an economical and efficient manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a schematic view of a temperature controllingapparatus according to some embodiments of the present disclosure.

FIG. 2 is a block diagram of a temperature controlling apparatusaccording to some embodiments of the present disclosure.

FIG. 3 illustrates a schematic view of a temperature controllingapparatus according to some embodiments of the present disclosure.

FIG. 4 illustrates a schematic view of a temperature controllingapparatus according to some embodiments of the present disclosure.

FIG. 5 illustrates a schematic view of a temperature controllingapparatus according to some embodiments of the present disclosure.

FIG. 6 is a block diagram depicting a process flow of a method forforming a photoresist layer according to some embodiments of the presentdisclosure.

FIG. 7 to FIG. 10 are schematic cross sectional views of various stagesin the process of forming a photoresist layer according to someembodiments of the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

In addition, terms, such as “first,” “second,” “third,” “fourth,” andthe like, may be used herein for ease of description to describe similaror different element(s) or feature(s) as illustrated in the figures, andmay be used interchangeably depending on the order of the presence orthe contexts of the description.

FIG. 1 illustrates a schematic view of a temperature controllingapparatus according to some embodiments of the present disclosure.Referring to FIG. 1, in an implementation of the disclosure, atemperature controlling apparatus 100 can be adopted as a part of antemperature control system for a wafer manufacturing process. Certainly,the application of the temperature controlling apparatus 100 is notlimited thereto. In some embodiments, the temperature controllingapparatus 100 includes a platen 110, a fluid source 120, a chiller 130,and a plurality of conduits 140, 150. In one of the implementations, theplaten 110 is configured to carry a wafer 10. The platen 110 can be, forexample, an electrostatic chuck. As such, an electrostatic force isapplied to the platen 110 for holding the wafer 10 securely during aspin coating process. In other embodiments, the platen 110 may be avacuum chuck or any suitable platen capable of holding the wafer 10securely with any suitable means. The fluid source 120 is configured tocontain a fluid therein for supplying the fluid. The chiller 130 isconnected to the fluid source 120 for cooling the fluid in the fluidsource 120 to a cooling temperature. In some embodiments, the chiller130 may include a fluid channel for circulating a refrigerant controlledto a desired temperature.

In some embodiments, the conduits 140, 150 are in fluid communicationwith the fluid source 120. As such, the fluid source 120 is configuredto supply the fluid to the conduits 140, 150. Each of the conduits 140and 150 includes a heater 146/156. The heaters 146 and 156 areconfigured to heat the fluids in the conduits 140 and 150 respectively,and the heating temperature of the fluid in one of the conduits 140/150is different from the heating temperature of the fluid in another one ofthe conduits 150/140. Namely, the fluids in the conduits 140 and 150 areheated to different temperatures by the heaters 140 and 156 in acontrollable manner respectively. The fluid heated by each of theheaters 146 and 156 may then be dispensed on the wafer 10 carried by theplaten 220 through each of the conduits 140 and 150.

In some embodiments, the temperature controlling apparatus 100 mayfurther include inlet thermal sensors 162, 164 and outlet thermalsensors 172, 174. The inlet thermal sensors 162, 164 are disposed atinlets 142, 152 of the conduits 140, 150 for sensing temperature of thefluid (before being heated) entering the conduits 140, 150 respectively.The outlet thermal sensors 172, 174 are disposed at outlets 144, 154 ofthe conduits 140, 150 for sensing temperature of the fluid (after beingheated) dispensed from the outlets 144, 154 respectively. The thermalsensors 162, 164, 172, 174 may be couple to a controller (e.g. thecontroller 180 shown in FIG. 2) of the temperature controlling apparatus100, such that the controller is configured to control the heaters 146,156 to heat the fluid to designated temperatures according to thesensing signals sent from the thermal sensors 162, 164, 172, 174.

For example, the conduits described above may include a first conduit140 and a second conduit 150. The first conduit 140 includes a firstinlet 142, a first outlet 144 and a first heater 146. In someembodiments, the first inlet 142 and the first outlet 144 are disposedon two opposite ends of the first conduit 140, and the first heater 146is disposed on the first conduit 140 and located between the first inlet142 and the first outlet 144. The first inlet 142 is in fluidcommunication with the fluid source 120, such that the fluid in thefluid source 120 cooled to the cooling temperature flows to the firstinlet 142 in a controllable manner. The first heater 146 is configuredto heat the fluid from the cooling temperature to a first heatingtemperature, and the fluid 12 a heated by the first heater 146 is thendispensed on the platen 110 through the first outlet 144 as shown inFIG. 1. In some embodiments, the first heating temperature of the fluid12 a in the conduits 140 may be substantially equal to or higher than22° C. and be substantially lower than 100° C. or the boiling point ofthe fluid 12 a, for example.

The second conduit 150 may be in a similar arrangement. For example, thesecond conduit 150 includes a second inlet 152, a second outlet 154 anda second heater 156. The second inlet 152 is in fluid communication withthe fluid source 120, such that the fluid in the fluid source 120 cooledto the cooling temperature flows to the second inlet 152 in acontrollable manner. The second heater 156 is configured to heat thefluid from the cooling temperature to a second heating temperature,wherein the second heating temperature is different from the firstheating temperature. In some embodiments, the second heating temperaturemay be substantially higher than 0° C. or the freezing point of thefluid 12 b and be substantially equal to or lower than 22° C., forexample, Then, the fluid 12 b heated by the second heater 156 isdispensed on the platen 110 through the second outlet 154. In otherwords, the fluids 12 a and 12 b in the first conduit 140 and the secondconduit 150 are heated to different temperatures by the first heater 146and the second heater 156 respectively, and the fluids 12 a and 12 bwith different temperatures are dispensed on the platen 110 through thefirst outlet 144 and the second outlet 154 respectively. It is notedthat two conduits 140, 150 are depicted herein for illustration purpose,but the number of the conduits of the temperature controlling apparatus100 is not limited thereto.

Accordingly, the fluids 12 a with the first heating temperature and thefluid 12 b with the second heating temperature may reach thermalequilibrium on the platen 110 to form a resultant layer 12 with adesired heating temperature. In some embodiments, the desired heatingtemperature of the resultant layer 12 may be substantially higher than0° C. or the freezing point of the fluid 12 a/12 b and be substantiallylower than 100° C. or the boiling point of the fluid 12 a/12 b. In someembodiments, the fluid 12 a from the first conduit 140 and the fluid 12b from the second conduit 150 may be dispensed on the platen 110sequentially. In other embodiments, the fluid in the first conduit 140and the fluid in the second conduit 150 may be dispensed on the platen110 at the same time. With such configuration, the temperaturecontrolling apparatus 100 can control the temperature of the fluid ineach conduit 140/150 and the temperature of the resultant layer 12formed on the platen 110 more precisely and efficiently. In someembodiments, the viscosity of the fluid is inversely proportional to thetemperature of the fluid. Namely, the higher the temperature of thefluid gets, the lower the viscosity of the fluid is. Accordingly, thethickness of the resultant layer 12 would be thinner when the viscosityof the resultant layer 12 is lower. Thereby, the thickness of theresultant layer 12 formed on the platen 110 can be controlled byadjusting the temperature of the fluid.

In some embodiments, the fluid may be a photoresist coating. Photoresistmaterials (e.g. polymer) are coated onto the wafer 10 by dispensing thephotoresist coating typically on the center of the wafer 10, and theplaten 110 carrying the wafer 10 may spin at high speeds for spreadingthe photoresist coating evenly on the wafer 10. In such embodiment, afirst photoresist coating 12 a heated to a first heating temperature bythe first heater 146 may be dispensed on the wafer 10, and a secondphotoresist coating 12 b heated to a second heating temperature by thesecond heater 156 may also be dispensed on the wafer 10. In someembodiments, the first heating temperature and the second heatingtemperature are both substantially higher than the cooling temperature.For example, the first heating temperature of the fluids 12 a in theconduits 140 may be substantially equal to or higher than 22° C. andsubstantially lower than 100° C. or the boiling point of the fluid 12 a.The second heating temperature of the fluid 12 b in the conduits 150 maybe substantially higher than 0° C. or the freezing point of the fluid 12a and substantially equal to or lower than 22° C. It is noted that thenumerical ranges described herein are merely for illustration purposeand the disclosure is not limited thereto. As such, the firstphotoresist coating 12 a and the second photoresist coating 12 b stackedon top of one another (or mixed together) form a photoresist layer 12 onthe wafer 10. With such configuration, the temperature and the viscosityof the photoresist layer 12 on the wafer 10 can be controlled byadjusting the first heating temperature of the first photoresist coating12 a and the second heating temperature of the second photoresistcoating 12 b. In some embodiments, when the photoresist layer 12 islower in viscosity, the photoresist layer 12 tends to spread out moreduring the spinning of the platen 110, and the viscosity of thephotoresist layer 12 is inversely proportional to the temperature of thephotoresist layer 12. Accordingly, the thickness of the photoresistlayer 12 formed on the wafer 10 can be controlled by adjusting thetemperatures of the first photoresist coating 12 a and the secondphotoresist coating 12 b.

In some embodiments, the inlet thermal sensor 162 is disposed at thefirst inlet 142 for sensing temperature (e.g. the cooling temperature)of the fluid entering the first conduit 140, and the inlet thermalsensor 164 is disposed at the second inlet 152 for sensing temperature(e.g. the cooling temperature) of the fluid entering the second conduit150. The outlet thermal sensor 172 is disposed at the first outlet 144for sensing temperature (e.g. the first heating temperature) of thefluid discharging from the first conduit 140, and the outlet thermalsensor 174 is disposed at the second outlet 154 for sensing temperature(e.g. the second heating temperature) of the fluid discharging from thesecond conduit 150. The thermal sensors 162, 164, 172, 174 may be coupleto the controller 180 of the temperature controlling apparatus 100, suchthat the controller is configured to control the heaters 146, 156 toheat the fluid to designated temperatures according to the sensingsignals sent from the thermal sensors 162, 164, 172, 174. Thereby, theheating temperature of the fluid 12 a/12 b dispensed from the conduit140/150 can be controlled and adjusted immediately (e.g. in real time)according to the feedback from the thermal sensors 162, 164, 172, 174.

FIG. 2 is a block diagram of a temperature controlling apparatusaccording to some embodiments of the present disclosure. In someembodiments, the platen 110 includes a plurality of temperature zones112, 114, 116, 118, and each of the temperature zones 112, 114, 116, 118includes a temperature adjusting element 112/114/116/118 embedded in theplaten 110, such that the temperature of the platen 110 can becontrolled regionally. In other words, the temperatures of the platen110 on different temperature zones 112, 114, 116, 118 can be controlledindependently. In some embodiments, the temperature adjusting elementssuch as heaters and/or chillers may be embedded in the temperature zones112, 114, 116, 118 and coupled to the controller 180 so as to controltemperature profile of the platen 110 by controlling the temperatureadjusting elements in the temperature zones 112, 114, 116, 118independently. In some embodiments, the temperature zones 112, 114, 116,118 include central temperature zones 114, 116 and peripheraltemperature zones 112, 118, wherein the central temperature zones 114,116 are located at a central region of the platen 110 while theperipheral temperature zones 112, 118 surround the central temperaturezone 114, 116 as shown in FIG. 2. With such configurations, thetemperatures of the central region and the peripheral region of thewafer 10 can be independently control in order to meet this processcondition. It is noted that the arrangement of the temperature zones112, 114, 116, 118 on the platen 110 is not limited thereto.

In some embodiments, the heater 146/156 of each of the conduits 140, 150may include an electrical resistance heater, a heater bar, an infraredheater, or any other suitable heater. In the embodiment of the heater146/156 being an electrical resistance heater, the first heater 146includes a first electrical resistance heater 146, and the second heater156 includes a second electrical resistance heater 156. The electricalresistance heaters 146, 156 may include electrical resistance coilswinding around the first conduit 140 and the second conduit 150. In someembodiments, each of the conduits 140 and 150 may include a metal ring147/157 surrounding each of the conduits 140 and 150. The electricalresistance coils of the electrical resistance heaters 146, 156 are incontact with the metal rings 147 and 157 respectively to heat up thefluid in the conduits 140 and 150. In some embodiments, the electriccurrent applied to the first electrical resistance heater 146 isdifferent from the electric current applied to the second electricalresistance heater 156, such that the fluids in the first conduit 140 andthe second conduits 150 can be heated to different temperatures in acontrollable manner. As such, the fluids 12 a, 12 b with differenttemperatures are dispensed on the platen 110 to form the resultant layer12 with a desired temperature. In some embodiments, the controller 180may be coupled to the first heater 146 and the second heater 156 tocontrol the electric current applied thereon according to the sensingsignals sent from the thermal sensors 162, 164, 172, 174. Thereby, theheating temperature of the fluid 12 a/12 b dispensed from the conduit140/150 can be adjusted immediately by controlling the electric currentapplied on the heater 146/156 according to the feedback from the thermalsensors 162, 164, 172, 174.

FIG. 3 illustrates a schematic view of a temperature controllingapparatus according to some embodiments of the present disclosure. It isnoted that the temperature controlling apparatus 100 a shown in FIG. 3contains many features same as or similar to the temperature controllingapparatus 100 disclosed earlier with FIG. 1 and FIG. 2. For purpose ofclarity and simplicity, detail description of same or similar featuresmay be omitted, and the same or similar reference numbers denote thesame or like components. The main differences between the temperaturecontrolling apparatus 100 a shown in FIG. 3 and the temperaturecontrolling apparatus 100 shown in FIG. 1 and FIG. 2 are described asfollows.

In some embodiments, the first heater 146 a includes at least one firstheater bar, the second heater 156 a includes at least one second heaterbar. In some embodiments, each of the conduits 140 and 150 may include ametal ring 147/157 surrounding each of the conduits 140 and 150. Theheater bars of heaters 146 a, 156 a are in contact with the metal rings147 and 157 respectively to heat up the fluid in the conduits 140 a and150 a. The contact area of first heater bar for contacting the firstconduit 140 a is different from the contact surface of the second heaterbar for contacting the second conduit 150 a, such that the fluids in thefirst conduit 140 a and the second conduits 150 a can be heated todifferent temperatures in a controllable manner. As such, the fluids 12a, 12 b with different temperatures are dispensed on the platen 110 toform the resultant layer 12 with a desired temperature.

In one of the implementations, the first heater 146 a may include aplurality of first heater bars (three heater bars are illustrated), andthe second heater 156 a includes a plurality of second heater bars(three heater bars are illustrated). Two of the first heater bars are incontact with the metal ring 147 of the first conduit 140 a, while merelyone of the second heater bars are in contact with the metal ring 157 ofthe second conduit 150 a. With such configuration, the contact area ofthe first heater bar is greater than the contact surface of the secondheater bar, so the first heating temperature of the fluids 12 a in thefirst conduit 140 a is higher than the second heating temperature of thefluids 12 b in the second conduits 150 a. In some embodiments, the firstheating temperature and the second heating temperature are bothsubstantially higher than the cooling temperature. For example, thefirst heating temperature of the fluids 12 a in the conduits 140 a maybe substantially equal to or higher than 22° C. and substantially lowerthan 100° C. or the boiling point of the fluid 12 a. The second heatingtemperature of the fluid 12 b in the conduits 150 a may be substantiallyhigher than 0° C. or the freezing point of the fluid 12 a andsubstantially equal to or lower than 22° C. It is noted that thenumerical ranges described herein are merely for illustration purposeand the disclosure is not limited thereto. In some embodiments, thecontroller 180 may be coupled to the first heater 146 a and the secondheater 156 a to control the contact area of each heater 146 a/156 a (orthe number of the heater bars contacting the conduits) according to thesensing signals sent from the thermal sensors 162, 164, 172, 174.Thereby, the heating temperature of the fluid 12 a/12 b dispensed fromthe conduit 140 a/150 a can be adjusted immediately by controlling thecontact area of the heater 146 a/156 a according to the feedback fromthe thermal sensors 162, 164, 172, 174.

FIG. 4 illustrates a schematic view of a temperature controllingapparatus according to some embodiments of the present disclosure. It isnoted that the temperature controlling apparatus 100 b shown in FIG. 4contains many features same as or similar to the temperature controllingapparatus 100 disclosed earlier with FIG. 1 and FIG. 2. For purpose ofclarity and simplicity, detail description of same or similar featuresmay be omitted, and the same or similar reference numbers denote thesame or like components. The main differences between the temperaturecontrolling apparatus 100 b shown in FIG. 4 and the temperaturecontrolling apparatus 100 shown in FIG. 1 and FIG. 2 are described asfollows.

In some embodiments, the first heater 146 b includes a first infraredheater 146 b, and the second heater 156 b includes a second infraredheater 156 b. The infrared heaters 146 b, 156 b with higher temperaturesare configured to transfer energy to the conduits 140, 150 with lowertemperatures through electromagnetic radiation. With such configuration,the distance D1 between the first infrared heater 146 b and the firstconduit 140 b is different from the distance D2 between the secondinfrared heater 156 b and the second conduit 150 b, such that the fluidsin the first conduit 140 b and the second conduits 150 b can be heatedto different temperatures in a controllable manner. As such, the fluids12 a, 12 b with different temperatures are dispensed on the platen 110to form the resultant layer 12 with a desired temperature. For example,the distance D1 between the first infrared heater 146 b and the firstconduit 140 b is substantially greater than the distance D2 between thesecond infrared heater 156 b and the second conduit 150 b as shown inFIG. 4. Accordingly, the first heating temperature of the fluids 12 a inthe first conduit 140 b is substantially lower than the second heatingtemperature of the fluids 12 b in the second conduits 150 b. Forexample, the first heating temperature of the fluids 12 a in theconduits 140 b may be substantially higher than 0° C. or the freezingpoint of the fluid 12 a and substantially equal to or lower than 22° C.The second heating temperature of the fluid 12 b in the conduits 150 bmay be substantially equal to or higher than 22° C. and substantiallylower than 100° C. or the boiling point of the fluid 12 b. It is notedthat the numerical ranges described herein are merely for illustrationpurpose and the disclosure is not limited thereto. In some embodiments,the controller 180 may be coupled to the first heater 146 b and thesecond heater 156 b to control the distance between each heater 146b/156 b and each conduit 140 b/150 b according to the sensing signalssent from the thermal sensors 162, 164, 172, 174. Thereby, the heatingtemperature of the fluid 12 a/12 b dispensed from the conduit 140 b/150b can be adjusted immediately by controlling the distance between theheater 146 b/156 b and the conduit 140 b/150 b according to the feedbackfrom the thermal sensors 162, 164, 172, 174.

FIG. 5 illustrates a schematic view of a temperature controllingapparatus according to some embodiments of the present disclosure. It isnoted that the temperature controlling apparatus 100 c shown in FIG. 5contains many features same as or similar to the temperature controllingapparatus 100 disclosed earlier with FIG. 1 and FIG. 2. For purpose ofclarity and simplicity, detail description of same or similar featuresmay be omitted, and the same or similar reference numbers denote thesame or like components. The main differences between the temperaturecontrolling apparatus 100 c shown in FIG. 5 and the temperaturecontrolling apparatus 100 shown in FIG. 1 and FIG. 2 are described asfollows.

In some embodiments, the temperature of the fluid in each conduit 140c/150 c can be controlled by mixing fluids with different temperatures.For example, the first conduit 140 c may include a plurality of firstpipelines 148 a, 148 b, 148 c, 148 d, which are in fluid communicationwith the fluid source 120 and the first conduit 140 c. In someembodiments, each of the first pipelines 148 a, 148 b, 148 c, 148 d mayinclude a flow control valve 149 such as solenoid valve coupled to thecontroller 180, such that the fluid from the fluid source 120 can flowinto the first conduit 140 c through the first pipelines 148 a, 148 b,148 c, 148 d in a controllable manner. The first heater described abovecan be disposed on at least one of the first pipelines 148 a, 148 b, 148c, and 148 d to heat the fluid therein. In some embodiments, eachpipelines 148 a, 148 b, 148 c, 148 d may be configured with its ownheater, and the temperature of the fluid in each of the pipelines 148 a,148 b, 148 c, and 148 d may be different from one another. Thecontroller 180 is coupled to the flow control valves 149 to control theamount of the fluid flowing from each pipelines 148 a, 148 b, 148 c, and148 d to obtain the desired temperature (e.g. the first heatingtemperature) of the fluid 12 a in the first conduit 140 c. In otherwords, the fluids with different temperatures from the first pipelines148 a, 148 b, 148 c, 148 d are mixed in the first conduit 140 c to reachthe desired temperature (e.g. the first heating temperature). Forexample, the first heating temperature may be substantially equal to orhigher than 22° C. and be substantially lower than 100° C. or theboiling point of the fluid.

Similarly, the second conduit 150 c may include a plurality of secondpipelines 158 a, 158 b, 158 c, 158 d, which are in fluid communicationwith the fluid source 120 and the second conduit 150 c. In someembodiments, each of the second pipelines 158 a, 158 b, 158 c, 158 d mayinclude a flow control valve 159 such as solenoid valve coupled to thecontroller 180, such that the fluid from the fluid source 120 can flowinto the second conduit 150 c through the second pipelines 158 a, 158 b,158 c, and 158 d in a controllable manner. The second heater describedabove can be disposed on at least one of the second pipelines 158 a, 158b, 158 c, and 158 d to heat the fluid therein. In some embodiments, eachpipelines 158 a, 158 b, 158 c, and 158 d may be configured with its ownheater, and the temperature of the fluid in each of the pipelines 158 a,158 b, 158 c, and 158 d may be different from one another. Thecontroller 180 is coupled to the flow control valves 159 to control theamount of the fluid flowing from each pipelines 158 a, 158 b, 158 c, and158 d, to obtain the desired temperature (e.g. the second heatingtemperature) of the fluid 12 b in the second conduit 150 c. In otherwords, the fluids with different temperatures from the second pipelines158 a, 158 b, 158 c, 158 d are mixed in the second conduit 150 c inorder to reach the desired temperature (e.g. the second heatingtemperature). For example, the second heating temperature may besubstantially higher than 0° C. or the freezing point of the fluid andsubstantially equal to or lower than 22° C. Thereby, the heatingtemperature of the fluid 12 a/12 b dispensed from the conduit 140 c/150c can be adjusted immediately by controlling the amount of the fluidflowing from each pipelines according to the feedback from the thermalsensors 162, 164, 172, 174.

FIG. 6 is a block diagram depicting a process flow of a method forforming a photoresist layer according to some embodiments of the presentdisclosure. FIG. 7 to FIG. 10 are schematic cross sectional views ofvarious stages in the process of forming a photoresist layer accordingto some embodiments of the present disclosure. With the temperaturecontrolling apparatus 100/100 a/100 b/100 c described above, a methodfor forming a photoresist layer can be developed. The method may includethe following steps.

At step S110 of FIG. 6, a first photoresist layer 12′ is formed on afirst wafer 10′ provided on a platen 110 as shown in FIG. 7. In someembodiments, the platen 110 is configured for supporting and spinningthe first wafer 10′. The platen 110 can be, for example, anelectrostatic chuck, which means an electrostatic force may be appliedto the platen 110 for supporting the wafer 10 securely during the spincoating process. In other embodiments, the platen 110 may be a vacuumchuck or any suitable platen capable of holding the wafer 10 securelywith any suitable means.

In some embodiments, the platen 110 includes a plurality of temperaturezones 112, 114, 116, 118 being at a first set of process temperaturesT1′, T2′, T3′, T4′. Namely, the temperature zone 112 is at the processtemperature T1′, the temperature zone 114 is at the process temperatureT2′, the temperature zone 116 is at the process temperature T3′, and thetemperature zone 118 is at the process temperature T4′. For the initialsetting, the process temperatures T1′, T2′, T3′, T4′ may be the same.Namely, the temperature profile of the whole platen 110 may be uniform.In some embodiments, for the initial setting, the process temperaturesT1′, T2′, T3′, T4′ may all be about 22° C., but the disclosure is notlimited thereto. The first photoresist layer 12′ may be dispensed ontothe platen 110 through the first outlet 144 and/or the second outlet154.

In some embodiments, the first wafer 10′ includes a metal layer 11′covering the process surface of the first wafer 10′. The firstphotoresist layer 12′ is formed on the metal layer 11′. In oneembodiment, the first photoresist layer 12′ may be formed by a firstphotoresist coating 12 a′ dispensed from the first outlet 144 and asecond photoresist coating 12 b′ dispensed from the second outlet 154.With such configuration, the temperature and the viscosity of thephotoresist layer 12′ on the wafer 10′ can be controlled by adjustingthe temperature of the first photoresist coating 12 a′ and thetemperature of the second photoresist coating 12 b′.

At step S120 of FIG. 6, a first etching process is performed on thefirst wafer 10′ to form a first patterned metal layer 11 a′ as shown inFIG. 8. The etching process performed on the metal layer 11′ is toremove where there is no first photoresist layer 12′ covering. Theetching process can be accomplished by either wet or dry etching. Then,a strip process is utilized to remove the first photoresist layer 12′and the resultant structure shown in FIG. 8 is obtained. In general,etching resistance of a photoresist layer is hard to control, and thedegree of etching performed on the first patterned metal layer 11 a′ maybe different. For example, the degree of etching may be more severe atthe center of the wafer 10′, while the degree of etching is milder atthe edge of the wafer 10′. As such, the etched pattern on the wafer 10′may be relatively rough and uneven as shown in FIG. 8.

At step S130 of FIG. 6, a profile variation of the first patterned metallayer 11 a′ with respect to a reference profile is determined. In someembodiments, to obtain the profile variation of the first patternedmetal layer 11 a′, a profile of the first patterned metal layer 11 a′after the first etching process is firstly measured by, for example, awafer inspection apparatus. Then, the profile of the first patternedmetal layer 11 a′ is compared with the reference profile, which is theprofile meant to achieve after the etching process.

Accordingly, the variation between the profile of the first patternedmetal layer 11 a′ and the profile meant to achieve is obtained. Forexample, in the embodiment shown in FIG. 8, the thickness of the firstpatterned metal layer 11 a on the right side is slightly thinner thanthat on the left side, which means the right side of the first patternedmetal layer 11 a′ is etched slightly more severe than the left side ofthe first patterned metal layer 11 a′.

At step S140 and step S150 of FIG. 6, referring to FIG. 9, the first setof process temperatures is adjusted to a second set of processtemperatures according to the profile variation. Then, a secondphotoresist layer is formed on a second wafer carried by the platen withthe temperature zones being at the second set of process temperaturesrespectively. In some embodiments, in order to fix the profilevariation, another photoresist layer with modified profile is formedaccording to the profile variation in order to adjust the etchingresistance, and the profile modification of the photoresist layer can beachieved by utilizing the viscosity of the photoresist coating beinginversely proportional to the temperature of the photoresist coating.

When the first photoresist layer 12′ is formed, the temperature zones112, 114, 116, 118 of the platen 110 are at the first set of processtemperatures T1′, T2′ T3′, T4′. In the present embodiment, the processtemperatures T1′, T2′, T3′, T4′ are the same. Namely, the firstphotoresist layer 12′ is formed on the platen 110 where the temperaturethereof being uniform, which results in the profile variation of thefirst patterned metal layer 11 a′. Therefore, the first set of processtemperatures T1′, T2′ T3′, T4 is adjusted to a second set of processtemperatures T1, T2, T3, T4 according to the profile variation. In thepresent embodiment, more etching resistance is needed on the right sideof the wafer since the thickness of the first patterned metal layer 11 aon the right side is slightly thinner than that on the left side.Accordingly, when a second wafer 10 is provided on the platen 110, theprocess temperatures T3, T4 of the temperature zones 116, 118 on theright side is adjusted to be slightly lower than the processtemperatures T1, T2 of the temperature zones 112, 114 on the left side.For example, the process temperatures T3, T4 of the temperature zones116, 118 on the right side are adjusted to be substantially higher than0° C. or the freezing point of the fluid and substantially equal to orlower than 22° C. The process temperatures T1, T2 of the temperaturezones 112, 114 on the left side are adjusted to be substantially equalto or higher than 22° C. and substantially lower than 100° C. or theboiling point of the fluid. It is noted that the numerical rangesdescribed herein are merely for illustration purpose and the disclosureis not limited thereto. As such, when the second photoresist layer 12 isformed on the second wafer 10 with the second set of processtemperatures T1, T2, T3, T4 applied thereon, the second photoresistlayer 12 is heated by the second set of process temperatures T1, T2, T3,T4 of the temperature zones 112, 114, 116, 118. Therefore, the viscosityof the second photoresist layer 12 on the right side would be slightlyhigher than the viscosity of the second photoresist layer 12 on the leftside since the viscosity of the second photoresist layer 12 is inverselyproportional to the temperature of the second photoresist layer 12. As aresult, the thickness of the second photoresist layer 12 on the rightside is slightly thicker than that on the left side as shown in FIG. 9.In addition, the platen 110 is spun to spread the second photoresistlayer 12. The higher viscosity makes the shear stress within thephotoresist layer larger, and the larger shear stress results in thickerphotoresist layer after spun. Accordingly, the thickness of the secondphotoresist layer 12 on the right side is slightly thicker than that onthe left side according to the profile variation of the first patternedmetal layer 11 a′ so as to provide more etching resistance on the rightside of the wafer 10.

Then, a second etching process is performed on the metal layer 11 on thesecond wafer 10 by utilizing the second photoresist layer 12 as a maskto form a second patterned metal layer 11 b as shown in FIG. 10. Withthe rectification described above, the profile variation of the secondpatterned metal layer 11 b with respect to the reference profile meantto achieve should be less than the profile variation of the firstpatterned metal layer 11 a′. If needed, the step S130 to step S150 canbe repeated until the profile variation of the patterned metal layerwith respect to the reference profile meant to achieve is less than apredetermined value. It is noted that the present embodiment is merelyfor illustration, the arrangement of the temperature zones and theprocess temperatures thereof can be adjusted according to actual profilevariation of the patterned metal layer and is not limited thereto.

In some embodiments, the second photoresist layer 12 can be formed bydispensing multiple photoresist coatings with different temperatures onthe platen 110. For example, a first photoresist coating 12 a heated tothe first heating temperature by the first heater of the temperaturecontrolling apparatus described above may be dispensed on the secondwafer 10, and a second photoresist coating 12 b heated to the secondheating temperature by the second heater described above may bedispensed on the second wafer 10. In some embodiments, the secondheating temperature is different from the first temperature. As such,the first photoresist coating 12 a and the second photoresist coating 12b stacked on top of one another (or mixed together) form the secondphotoresist layer 12 having a third temperature on the wafer 10. Withsuch arrangement, the temperature and the viscosity of the photoresistlayer 12 on the wafer 10 can be controlled by adjusting the firstheating temperature of the first photoresist coating 12 a and the secondheating temperature of the second photoresist coating 12 b. Accordingly,the thickness of the photoresist layer 12 formed on the wafer 10 canfurther be controlled by adjusting the temperatures of the firstphotoresist coating 12 a and the second photoresist coating 12 b.

Based on the above discussions, it can be seen that the presentdisclosure offers various advantages. It is understood, however, thatnot all advantages are necessarily discussed herein, and otherembodiments may offer different advantages, and that no particularadvantage is required for all embodiments.

In accordance with some embodiments of the disclosure, a temperaturecontrolling apparatus includes a platen, a fluid source, a chiller, afirst conduit and a second conduit. The fluid source is configured forsupplying a fluid. The chiller is coupled to the fluid source forcooling the fluid in the fluid source to a cooling temperature. Thefirst conduit includes a first inlet in fluid communication with thefluid source, a first outlet and a first heater configured to heat thefluid from the cooling temperature to a first heating temperature,wherein the fluid heated by the first heater is dispensed on the platenthrough the first outlet. The second conduit includes a second inlet influid communication with the fluid source, a second outlet and a secondheater configured to heat the fluid from the cooling temperature to asecond heating temperature different from the first heating temperature,wherein the fluid heated by the second heater is dispensed on the platenthrough the second outlet.

In accordance with some embodiments of the disclosure, a temperaturecontrolling apparatus includes a fluid source, a chiller, a plurality ofconduits, and a platen. The fluid source is configured for supplying afluid. The chiller is coupled to the fluid source for cooling the fluidin the fluid source to a cooling temperature. The conduits are in fluidcommunication with the fluid source. Each of the conduits includes aheater configured to heat the fluid in each of the conduits. A heatingtemperature of the fluid in one of the conduits is different from aheating temperature of the fluid in another one of the conduits. Theplaten is configured to carry a wafer, wherein the fluid heated by eachof the heaters is dispensed on the wafer through each of the conduits.

In accordance with some embodiments of the disclosure, a method forforming a photoresist layer includes the following steps. A firstphotoresist layer is formed on a first wafer carried by a platen,wherein the platen includes a plurality of temperature zones being at afirst set of process temperatures. A first etching process is performedon the first wafer to form a first patterned metal layer. A profilevariation of the first patterned metal layer with respect to a referenceprofile is determined. The first set of process temperatures is adjustedto a second set of process temperatures according to the profilevariation. A second photoresist layer is formed on a second wafercarried by the platen with the temperature zones being at the second setof process temperatures respectively.

In accordance with some embodiments of the disclosure, a method forforming a photoresist layer includes the following steps. A firstphotoresist layer is formed on a first wafer provided on a platen. Theplaten includes a first temperature zone being at a first processtemperature and a second temperature zone being at a second processtemperature. A first etching process is performed on the first wafer toform a first patterned metal layer. A profile variation of the firstpatterned metal layer with respect to a reference profile is determined.The second process temperature is adjusted to a third processtemperature different from the second process temperature according tothe profile variation. The third process temperature is different fromthe second process temperature. A second photoresist layer is formed ona second wafer provided on the platen with the first temperature zonebeing at the first process temperature and the second temperature zonebeing at the third process temperature.

In accordance with some embodiments of the disclosure, a method forforming a photoresist layer includes the following steps. A firstphotoresist layer is formed on a first wafer provided on a platen. Theplaten includes a plurality of temperature zones being at a first set ofprocess temperatures. A first etching process is performed on the firstwafer to form a first patterned metal layer. A profile of the firstpatterned metal layer is measured by a wafer inspection apparatus. Themeasured profile of the first patterned metal layer is compared with areference profile to obtain a profile variation. The first set ofprocess temperatures is adjusted to a second set of process temperaturesaccording to the profile variation. One of the process temperatures ofthe second set of process temperatures is different from another one ofthe process temperatures of the second set of process temperatures. Asecond photoresist layer is formed on a second wafer provided on theplaten with the temperature zones being at the second set of processtemperatures respectively.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method for forming a photoresist layer,comprising: forming a first photoresist layer on a first wafer providedon a platen, wherein the platen comprises a plurality of temperaturezones being at a first set of process temperatures; performing a firstetching process on the first wafer to form a first patterned metallayer; determining a profile variation of the first patterned metallayer with respect to a reference profile; adjusting the first set ofprocess temperatures to a second set of process temperatures accordingto the profile variation; forming a second photoresist layer on a secondwafer provided on the platen with the temperature zones being at thesecond set of process temperatures respectively.
 2. The method forforming the photoresist layer as claimed in claim 1, wherein forming thesecond photoresist layer on the second wafer comprises: forming a firstphotoresist coating on the second wafer, wherein the first photoresistcoating has a first temperature; and forming a second photoresistcoating on the second wafer, wherein the second photoresist coating hasa second temperature different from the first temperature, the firstphotoresist coating and the second photoresist coating form the secondphotoresist layer having a third temperature.
 3. The method for formingthe photoresist layer as claimed in claim 1, wherein the secondphotoresist layer is heated by the second set of process temperatures ofthe temperature zones, and a viscosity of the second photoresist layeris inversely proportional to a temperature of the second photoresistlayer.
 4. The method for forming the photoresist layer as claimed inclaim 1, wherein forming the second photoresist layer on the secondwafer further comprises: spinning the platen to spread the secondphotoresist layer.
 5. The method for forming the photoresist layer asclaimed in claim 1, wherein the first set of process temperaturescomprises a first process temperature and a second process temperature,the first process temperature is equal to the second processtemperature, the plurality of temperature zones comprises a firsttemperature zone and a second temperature zone, and forming the firstphotoresist layer comprises setting the first temperature zone at thefirst process temperature and setting the second temperature zone at thesecond process temperature.
 6. The method for forming the photoresistlayer as claimed in claim 5, wherein the second set of processtemperatures comprises a third process temperature and a fourth processtemperature, the third process temperature is different from the fourthprocess temperature, and forming the second photoresist layer comprisessetting the first temperature zone at the third process temperature andsetting the second temperature zone at the fourth process temperature.7. The method for forming the photoresist layer as claimed in claim 6,wherein the third process temperature is equal to the first processtemperature and the second process temperature.
 8. The method forforming the photoresist layer as claimed in claim 1, wherein the firstphotoresist layer is formed to have a substantially uniform thickness.9. The method for forming the photoresist layer as claimed in claim 1,wherein the second photoresist layer is formed to have a non-uniformthickness.
 10. A method for forming a photoresist layer, comprising:forming a first photoresist layer on a first wafer provided on a platen,wherein the platen comprises a first temperature zone being at a firstprocess temperature and a second temperature zone being at a secondprocess temperature; performing a first etching process on the firstwafer to form a first patterned metal layer; determining a profilevariation of the first patterned metal layer with respect to a referenceprofile; adjusting the second process temperature to a third processtemperature different from the second process temperature according tothe profile variation; forming a second photoresist layer on a secondwafer provided on the platen with the first temperature zone being atthe first process temperature and the second temperature zone being atthe third process temperature.
 11. The method for forming thephotoresist layer as claimed in claim 10, wherein forming the secondphotoresist layer on the second wafer comprises: forming a firstphotoresist coating on the second wafer, wherein the first photoresistcoating has a first temperature; and forming a second photoresistcoating on the second wafer, wherein the second photoresist coating hasa second temperature different from the first temperature, the firstphotoresist coating and the second photoresist coating form the secondphotoresist layer having a third temperature.
 12. The method for formingthe photoresist layer as claimed in claim 10, wherein a viscosity of thesecond photoresist layer is inversely proportional to a temperature ofthe second photoresist layer.
 13. The method for forming the photoresistlayer as claimed in claim 10, wherein forming the second photoresistlayer on the second wafer further comprises: spinning the platen tospread the second photoresist layer.
 14. The method for forming thephotoresist layer as claimed in claim 10, wherein the first photoresistlayer is formed to have a substantially uniform thickness.
 15. Themethod for forming the photoresist layer as claimed in claim 10, whereinthe second photoresist layer is formed to have a non-uniform thickness.16. A method for forming a photoresist layer, comprising: forming afirst photoresist layer on a first wafer provided on a platen, whereinthe platen comprises a plurality of temperature zones being at a firstset of process temperatures; performing a first etching process on thefirst wafer to form a first patterned metal layer; measuring a profileof the first patterned metal layer by a wafer inspection apparatus;comparing the measured profile of the first patterned metal layer with areference profile to obtain a profile variation; adjusting the first setof process temperatures to a second set of process temperaturesaccording to the profile variation, wherein one of the processtemperatures of the second set of process temperatures is different fromanother one of the process temperatures of the second set of processtemperatures; forming a second photoresist layer on a second waferprovided on the platen with the temperature zones being at the secondset of process temperatures respectively.
 17. The method for forming thephotoresist layer as claimed in claim 16, wherein forming the secondphotoresist layer on the second wafer comprises: forming a firstphotoresist coating on the second wafer, wherein the first photoresistcoating has a first temperature; and forming a second photoresistcoating on the second wafer, wherein the second photoresist coating hasa second temperature different from the first temperature, the firstphotoresist coating and the second photoresist coating form the secondphotoresist layer having a third temperature.
 18. The method for formingthe photoresist layer as claimed in claim 16, wherein the secondphotoresist layer is heated by the second set of process temperatures ofthe temperature zones, and a viscosity of the second photoresist layeris inversely proportional to a temperature of the second photoresistlayer.
 19. The method for forming the photoresist layer as claimed inclaim 16, wherein forming the second photoresist layer on the secondwafer further comprises: spinning the platen to spread the secondphotoresist layer.
 20. The method for forming the photoresist layer asclaimed in claim 16, wherein the first photoresist layer is formed tohave a substantially uniform thickness and the second photoresist layeris formed to have a non-uniform thickness.